The laboratory of in vitro marrow culture is concerned with granulopoiesis and granulopoietic regulation. During the past year the in vitro - in vivo effects of hyperthermia to 42 degrees F have been examined in normal human and murine bone marrow and peripheral blood. Clinical hyperthermia effects on peripheral blood CFU-C have been documented. The effect of immunostimulation on in vivo - in vitro granulopoiesis has been investigated. A clinical correlation confirming in vitro observations of the relative marrow sparing effect of the new nitrosourea chlorozotocin in comparison to BCNU was completed. A new photometric scanner has been developed to improve statistical results with human CFU-C. Future projects are designed to study the temporal relationship of the additive toxic effect of hyperthermia and various classes of chemotherapeutic agents on human CFU-C and human cultures; to develop and purify a new CSF from human mammary tumor; and to differentiate whether the stimulation of granulopoiesis by BCG immunostimulation is a direct response of CFU-C or results from an increased macrophage CSA production. BIBLIOGRAPHIC REFERENCES: Pinedo, H., Zaharko, D., Bull, J., and Chanber, B.: The relative contribution of drug concentration and duration of exposure to mouse bone marrow toxicity during continuous methotrexate infusion. Ca. Res. 37: 445-450, 1977. Tormey, D.C., Simon, R.M., Falkson, G., Bull, J., Band, P., Perlin, E., and Blom, J.: Evaluation of adriamycin and dibromodulcitol in metastatic breast cancer. Ca. Res. 37: 529-534, 1977.